# DQMP Forum - Quench Dynamics of Coupled Luttinger Liquids - NMR Studies of the Perovskite Rare-earth Nickelates

16.03.2021 13:00 – 14:30

Quench Dynamics of Coupled Luttinger Liquids

Paola Ruggiero (group of prof. Giamarchi)

Quantum systems in low-dimensions are special in that the eﬀects of strong correlations and interactions are enhanced and lead to dramatic eﬀects. A celebrated example from condensed matter physics is the breakdown of Landau’s Fermi liquid theory in 1D, which is replaced by the Luttinger liquid (LL) paradigm. The latter has been largely employed to study both equilibrium and out-of-equilibrium problems, with particular reference in more recent times to the dynamics generated after a quantum quench protocol. In this last case, while a lot is known for a single LL, less is known when two (or more) of them are coupled: this situation is relevant, for example, for the quench dynamics in the Hubbard model, or in tunnel-coupled tubes in cold atoms experiments.

This problem was initially studied under the assumption for the two LLs to be identical, which leads to major simpliﬁcations. Recently, instead, a couple of works considered the quench dy-namics of two diﬀerent LL, aiming at understanding the eﬀect of the imbalance between them. In our contributions, the problem was solved at ﬁrst relying on semiclassical approximation [1]. This approximation gives access already to a very rich phenomenology,with (i) the emergence of multiple light cones, separating diﬀerent decaying regimes; (ii) a prethermal regime even-tually decaying into a quasi-thermal one; (iii) non-trivial effects of a non-zero temperature in the initial state. We then extended such results to more general situations relying on Conformal Fiel Theory methods

NMR Studies of the Perovskite Rare-earth Nickelates

Lukas Korosec (group of prof. Triscone)

The perovskite rare-earth nickelates (RE NiO3) are complex oxide materials that are well-known for their strongly-correlated electron physics. Their phase diagram contains paramagnetic metallic, paramagnetic insulating, and antiferromagnetic insulating phases. In the insulating phases, a structural modulation by alternating large and small NiO6 octahedra is observed, which has often been interpreted as an eﬀect of a charge disproportionation. Antiferromagnetic order occurs at the unusual wavevector (1/4, 1/4, 1/4)pc, with four Ni sites per period. Nuclear magnetic resonance (NMR) spectroscopy in 17O-enriched samples has offered a new experimental perspective on these materials the nuclear electric quadrupole moment can act as a probe for charge disproportionation n this system. Nuclear spin relaxation has allowed us to study the magnetic dynamics of the antiferromagnetic state, the role of magnetic ﬂuctuations in the phase transitions of RE NiO3, and the nature of the metallic phase.

### Lieu

By zoom meeting

### Organisé par

Département de physique de la matière quantiqueentrée libre

### Classement

Catégorie: Forum